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Showing papers on "Langmuir published in 1979"


Journal ArticleDOI
TL;DR: In this article, the adsorption of human serum albumin on precipitated stoichiometric hydroxyapatite Ca10(PO4)6(OH)2, /CaHA/ was followed in a wide pH range.

119 citations


Journal ArticleDOI
01 Aug 1979-Polymer
TL;DR: In this article, the molar enthalpy for gas sorption in glassy polymers at a fixed concentration, often called the isosteric enthalpies of sorption, exhibits a clearly discernable minimum when plotted as a function of penetrant concentration.

86 citations


Journal ArticleDOI
TL;DR: In this article, the complex plane analysis of a cell impedance in the case of a surface redox system (strong adsorption of both O and R) is treated theoretically.

84 citations


Journal ArticleDOI
01 Oct 1979-Fuel
TL;DR: For four Kentucky coals, a comparison was made between pore volume distribution evaluated from CO2 adsorption isotherms calculated from the Cranston-Inkley method and the Medek method.

69 citations


Journal ArticleDOI
01 Jan 1979
Abstract: Kinetic equations for the solubility of silica in HF — HCI aqueous mixtures based on a molecular model for the reactivity of silica surface with this medium arc proposed.These kinetic equations postulate a first order dependence on the HF2 - ion concentration in the solution, and a dependence on H+ expressed by Langmuir’s isotherm.The experimental results obtained confirm that the time averaged rate of silica dissolution follows a first order dependence on [HF2- - ].The Arrhenius plot of In kr versus 1/T is linear. The over-all activation energy of solubility is 9, 7 ± 0, 3 kcal.The rates reported over the temperature range 30-69,5 °C and HF concentration 1,15-2,56 M HF show a definite dependence on HCI concentration. The use of Langmuir’s isotherm appears as correct, in the region of weak acid concentration (first order relation in respect to H+ ) but further experiments have to be made to ascertain this in the region of higher acid concentrations.

24 citations


Journal ArticleDOI
TL;DR: In this paper, the adsorption isotherms of Ca2+, Sr2+ and Ba2+ ions on anatase were determined at pH 7 and at 10, 25 and 45°C by complexometric titration.

19 citations


Journal ArticleDOI
TL;DR: In this article, a comparative kinetic analysis of the Langmuir and Jovanovic models for adsorption of gases on solid surfaces is presented, taking into account of the settling times distribution of the adsorbed molecules on the surface.

16 citations


Journal ArticleDOI
TL;DR: Sorptive interactions between Escherichia coli and a purified allophane clay fraction were studied quantitatively using electronic particle counting and electrophoresis and yielded adsorption isotherms that obeyed single-term Langmuir kinetics.
Abstract: Sorptive interactions between Escherichia coli (ATCC 11303B) and a purified allophane clay fraction were studied quantitatively using electronic particle counting and electrophoresis. Adsorption was influenced by pH and ions present at the allophane surface. These effects could be rationalized by considering changes in the net surface charge of the components. Electronic particle counting studies at pH 5.5 and above gave adsorption isotherms that obeyed single-term Langmuir kinetics. At pH 4.5, a more complex two-step isotherm was obtained, which was attributed to aggregation of unadsorbed cells by Al solubilized from the allophane surface.

14 citations


Journal ArticleDOI
TL;DR: The adsorption of an organic high molecular polyphosphonate on bovine enamel and synthetic hydroxyapatite has been studied and Adsorption kinetics seem to obey Langmuirs equation.
Abstract: The adsorption of an organic high molecular polyphosphonate on bovine enamel and synthetic hydroxyapatite has been studied. Concentration and particle size of the solids and also pH and concentration of the phosphonate solution are important parameters for the amount of adsorbed polyphosphonate. During adsorption of the polyphosphonate, phosphate ions are released in solution. This observation correlates with the results of adsorption experiments in which low molecular diphosphonates were used. Adsorption kinetics seem to obey Langmuirs equation. The affinity constants and the binding capacities are calculated.

13 citations


Journal ArticleDOI
TL;DR: In this article, a frequency dispersion of conductance has been observed in a heterogeneous multilayer system of Cd•behenate and Cd−stearate in accordance with the hopping theory of the multi-layer assemblies.
Abstract: A frequency dispersion of conductance has been observed in a heterogeneous multilayer system of Cd‐behenate and Cd‐stearate in accordance with the hopping theory of the multilayer assemblies. The values of the single‐layer dc conductance evaluated for Cd‐behenate are consistent with those for palmitate, stearate, and arachidate, suggesting the availability of the heterogeneous multilayer system for the evaluation of the bulk conductivity of a single monolayer.

13 citations


Journal ArticleDOI
01 Oct 1979-Talanta
TL;DR: The adsorption characteristics of mercury(II) on several kinds of styrene-divinylbenzene copolymer beads having different surface properties were studied and it was found that the polymer beads selectively adsorbed mercury( II) from solutions over a wide range of pH with high efficiency.

Journal ArticleDOI
TL;DR: In this article, the authors clarified that the constant pattern behavior is established even for binary component systems in relatively long columns and under favorable adsorption isotherms, and that intraparticle diffusion is approximated by the linear-driving force (LDF) approximation with good accuracy for bicomponent systems.
Abstract: In a separate paper2) the authors clarified that the so-called constant pattern (CP) behavior is established even for binary component systems in relatively long columns and under favorable adsorption isotherms, and that intraparticle diffusion is approximated by the linear-driving force (LDF) approximation with good accuracy for bicomponent systems. Cooney and Strusi^ found that a linear relation holds between the fluid-phase concentrations of two interacting components when the ratio of the overall mass transfer coefficients is unity, and they have derived an analytical solution for calculating the breakthrough (BT) curves for a special case of the Langmuir isotherm system. However, they did not clarify the conditions under which the solution is applicable, nor verify the solution experimentally. Furthermore, they used


Journal ArticleDOI
TL;DR: In this paper, the Jovanovic isotherm is derived using an erroneous assumption concerning the rate of adsorption, and the correct fomulation is used in the derivation.
Abstract: It is shown that the Jovanovic isotherm is derived using an erroneous assumption concerning the rate of adsorption. When the correct fomulation is used in the derivation the resultant isotherm is that due to Langmuir.

Journal ArticleDOI
TL;DR: In this paper, Langmuir films based on cadmium stearate have been successfully deposited on to the surface of p-type CdTe and measured C/V curves show, for the first time, the accumulation, depletion and weak-inversion regions typical of an ideal device.
Abstract: Langmuir films based on cadmium stearate have been successfully deposited on to the surface of p-type CdTe. The measured C/V curves show, for the first time, the accumulation, depletion and weak-inversion regions typical of an ideal device. The G/V curves show a sharp peak in the depletion region at high frequencies which is thought to be due to losses at interface states. An initial estimate of the density yields an average value of 1011 states cm- 2 .

Journal ArticleDOI
TL;DR: In this article, the authors studied the adaption of Cu(II) on activated sludge from the treatment of municipal sewage, and the resulting adsorption isotherm is of the Langmuir type.
Abstract: Adsorption of Cu(II) on activated sludge from the treatment of municipal sewage is studied. The resulting adsorption isotherm is of the Langmuir type.

Journal ArticleDOI
TL;DR: In this article, the adsorption of colloidal trivalent iron on neutral, acid and basic Al2O3 from aqueous solution as a function of pH has been studied.
Abstract: The adsorption of colloidal trivalent iron on neutral, acid and basic Al2O3 from aqueous solution as a function of pH has been studied. The dependence of sorption of pH is characterized by a maximum, whose position depends on the nature of colloidal particles and surface properties of the sorbents. Adsorption isotherms for the given range of sorbent loading can be expressed by the Langmuir adsorption equation.

Journal ArticleDOI
TL;DR: The Langmuir parameters of orthophosphate and pyrophosphate (PP) sorption for the ammoniated tropical soils were determined in this paper, where positive linear relationships between OP and PP sorption maxima and amounts of anhydrous NH3 added were noticed.
Abstract: The Langmuir parameters of orthophosphate (OP) and pyrophosphate (PP) sorption for the ammoniated tropical soils were determined. Positive linear relationships between OP and PP sorption maxima and amounts of anhydrous NH3 added were noticed. Indexes of bonding energy of OP and PP increased exponentially as ammoniation level of the soils increased from 33 to 100% of ammonia retention capacity.

Journal ArticleDOI
TL;DR: In this article, the effects of temperature and solvent on the adsorption of CTA and CAB on porous adsorbents (calcium silicate, aluminium silicate and cellulose powder) have been studied.
Abstract: The effects of temperature and solvent on the adsorption of CTA and CAB on porous adsorbents (calcium silicate, aluminium silicate, and cellulose powder) have been studied. The adsorption of polymers is found to increase with increase in temperature. The values of heat of adsorption (ΔHad) have been obtained from the adsorption data. The studies of adsorption from different solvents indicated that the polymer adsorption is dependent on two factors: polymer-adsorbent and polymer/solvent interactions. The adsorption data are also treated with Langmuir, Simha-Frisch-Eirich, Gilliland and Guttoff, Forsman and Hughes, and Silberberg theories. Die Einflusse von Temperatur und Losungsmittel auf die Adsorption von CTA und CAB auf porosen Adsorptionsmitteln (Calciumsilikat, Aluminiumsilikat und Cellulosepulver) wurden untersucht. Die Adsorption nimmt mit steigender Temperatur zu. Die Adsorptionswarmen (ΔHad) wurden aus den Adsorptionsdaten erhalten. Die Untersuchungen der Adsorption aus verschiedenen Losungsmitteln zeigten, das die Polymer-Adsorption von Wechselwirkungen zwischen Polymerem und Adsorptionsmittel und zwischen Polymerem und Losungsmittel abhangt. Die Adsorptionsdaten wurden nach den Theorien von Langmuir, Simha-Frisch-Eirich, Gilliland und Guttoff, Forsman und Hughes sowie Silberberg dargestellt.


Journal ArticleDOI
TL;DR: In this paper, the authors used rice husk (RH) and Rice husk ash (RHA) as low cost adsorbent to remove methylene blue (MB) from aqueous solution by batch sorption technique.
Abstract: In this study, the rice husk (RH) and rice husk ash (RHA) were used as a low cost adsorbent to remove methylene blue (MB) from aqueous solution by batch sorption technique. Effects of initial dye concentration, solution pH, and adsorbent dose on sorption were studied. It was shown that the percent removal also increased when the adsorption capacity (qe) were increased. In the batch system, the adsorption capacity was increased when the parameters were increased until it achieved the equilibrium. The Langmuir and Freundlich’s models were applied to the data related to adsorption isotherm. The optimal parameters for this experiment were 7.5ppm for initial concentration, 0.6g adsorbent dosage and pH 5.8. In the batch system, the adsorption capacity was increased when the parameters were increased until it achieved the equilibrium. The RHA could be employed as the more effective low oval of Methylene Blue Dye from aqueous solution.

Journal ArticleDOI
TL;DR: In this article, the congruency of adsorption isotherms with respect to both electrode charge (σM) and potential (E) was evaluated through double layer capacity measurements.
Abstract: Adsorption of ethylene glycol, propan-1,2-diol and butan-1,4-diol at the Hg/0.10 mol kg–1 KCl (aq.) solution interface evaluated through equilibrium double layer capacity measurements indicated congruency of adsorption isotherms with respect to both electrode charge (σM) and potential (E); applicability of Langmuir's adsorption isotherm; quadratic dependence of Δtext-decoration:overlineG° on E and single stable orientation with the hydrocarbon chain facing the electrode and functional group in solution throughout the coverage region for all these compounds. Surface excess, standard free energy of adsorption and the anodic shift of Epzc are in the order: ethylene glycol < propan-1,2-diol < butan-1,4-diol. The shift of charge corresponding to maximum adsorption towards less negative charges in passing from ethylene glycol to butan-1,4-diol has been explained with the help of an equation given by Damaskin and Frumkin.


Book ChapterDOI
TL;DR: In this article, the adsorption mechanism of chlordimeform (N'-(4-chloro-2-methylphenyl)-N,N-dimethylmethanimidamide hydrochloride) by Wyoming montmorillonite containing different exchangeable cations (Na +, K +, Mg ++ and Ca ++ ) has been investigated.
Abstract: The adsorption mechanism of the pesticide chlordimeform (N'-(4-chloro-2-methylphenyl)-N,N-dimethylmethanimidamide hydrochloride) by Wyoming montmorillonite containing different exchangeable cations (Na + , K + , Mg ++ and Ca ++ ) has been investigated. The adsorption isotherms of chlordimeform in aqueous solutions on the clay have been measured and they are of “L” or Langmuir type. The corresponding values of adsorption maxima in single-layer complexes are about 1.1 mmol g −1 in agreement with the equivalent area of the clay, obtained from the layer charge. The adsorption of chlordimeform on clay is essentially a cation exchange reaction, increasing with temperature, in which the exchangeable inorganic cations are released into the solution. The “L” type isotherms, X-ray diffraction and infrared spectra suggest that the chlordimeform ions lie flat between the silicate layers. Interlayered pesticide is difficult to displace with distilled water or aqueous solutions of inorganic cations.

Journal ArticleDOI
TL;DR: In this article, the cylindrical Langmuir probe under orbital-limited conditions was used to determine the charge density in a low-density collisional plasma, and the results indicated that the length of the probe significantly affects the probe characteristics.
Abstract: The cylindrical Langmuir probe under orbital-limited conditions was used to determine the charge density in a low-density collisional plasma. The Langmuir's theory was applied to both electron and ion saturation currents in their respective accelerating regions. Present study indicates that the length of the probe significantly affects the probe characteristics. A probe of suitable length under orbital-limited conditions may be useful under the experimental conditions where the radius of the probe is much smaller than the Debye lengt.